1. Field of the Invention
The present invention relates to a multicylinder internal combustion engine which may be assembled from the top side of the engine without the need for accessing internal parts through a lower portion of the engine.
2. Related Art
Reciprocating internal combustion engines utilizing a crankshaft upon which a number of pistons and connecting rods are mounted typically require that assembly of the engine proceed with operations accessed from not only the top portion of the engine, but also the lower portion of the engine. Thus, when mounting a crankshaft within a conventional internal combustion engine, a cylinder block must be accessed from a lower portion of the engine, so as to allow the crankshaft to be placed into contact with the block, and secured with main bearing caps placed from underneath the engine. Then, pistons and connecting rods are inserted from the top of the engine; once again the fastenings for the connecting rod caps must be applied from underneath the engine. This assembly technique causes unfortunate problems in the context of many usages of internal combustion engines. For example, in marine usage, it is often very difficult to obtain access to the lower portion of an engine once it has been installed in a vessel. Similarly, with many vehicle usages and even stationary usage of reciprocating engines, access to the lower portion of the crankcase is difficult, which makes it extremely difficult to work on the engine in place. This, in turn, frequently necessitates expensive and time-consuming removal of the engine to allow it to be properly serviced. Moreover, known internal combustion engines which have suffered spun main bearings or other bearing damage often require expensive and technically difficult resurfacing of the main bearing bores. And, extensive damage in the area of the main bearing bores often necessitates the scrapping of motor blocks, at concomitantly high expense.
It would be desirable to provide an internal combustion engine assembled almost completely from the top of the engine, while at the same time offering completely renewable main bearing bores, so as to avoid both the need to resurface main bearing bores in the field, as well as the scrapping of engines having heavily damaged main bearing bores.